Later, on CNN's Piers Morgan Tonight, the host asked Guggenheim what negatives about Obama made their way into the documentary-style video. Guggenheim couldn't name any, but cited as a negative "too many accomplishments" by the president to squeeze into a 17-minute production.

Speaking Friday in Jackson, Miss., Romney belittled what he called the "infomercial" and Guggenheim's inability to find anything bad to say about the president's first three years in office.

"I'll tell you, I've got a long list of people for that producer to talk to," Romney said, as NPR's Ari Shapiro reports. "If someone's looking for things that the president's done wrong, it's a long, long, long list."

Romney wasn't alone in mocking the filmmaker. During Thursday's interview, Guggenheim told CNN's Morgan he "took a pay cut" to make the movie.

"I'm surprised you weren't paying [Obama], by the sound of it," responded Morgan. "For the sheer honor and joy."